While technology that tracks cellphones and cars has made work easier for some law enforcement officials, a bundle of proposed laws would ensure that the same technology could not violate Marylanders' protections from unwarranted searches and seizures.

Members of the American Civil Liberties Union of Maryland testified Thursday in the House Judiciary Committee and the Senate Judicial Proceedings Committee in favor of four bills aimed at curbing law enforcement officials' ability to electronically monitor citizens.

If passed, the bills would require law enforcement to obtain a warrant before reading electronic communication and tracking a cellphone.

"Your phone can tell the government where you are at any moment," said Del. Jeff Waldstreicher, D-Montgomery, who sponsored the bill on cellphone tracking.

The proposed bills would also limit the ability of police to use drones, and would place parameters on how long law enforcement officials can keep records based on license plate readers.

David Rocah, senior staff attorney with the ACLU, said he is concerned that laws requiring warrants did not yet exist when smartphones became available to the public.

"Our statutes have not kept pace with our technology," he said.

Supporters of the bill said historic data in phones that give information about a phone owner's previous device use are less precise than real-time information.

But the technology is evolving and with more smartphones, the data about an individual user is becoming clearer, Rocah said.

"And the number of cellphone towers is only going to increase," he said.

Some law enforcement officials who oppose the bill on cellphone tracking testified that the bill would hinder their ability to do their jobs.

"The only person that this bill serves are criminals," said Wesley Adams, chief of the homicide division for the Prince George's County State's Attorney and a Republican candidate for Anne Arundel County State's Attorney.

During his testimony, Adams said his division once tracked the location of the last phone call from a homicide victim's cellphone in order to catch a suspect.

However, Rocah said some of the legislation, such as the license-plate tracking bill and the electronic communication bill, would prevent historic data about an individual citizen's technology use from building up.

But Charlie Smith, state's attorney for Frederick County, said there is a long statute of limitation on some crimes, and older data often helps law enforcement solve long-term cases.

Law enforcement officials who opposed the bill on electronic communication said monitoring an individual citizen requires too much time and money to become a major concern.

"I don't think any of us are bored enough to be sitting around reading someone's emails," said Jonathan Newell, state's attorney for Caroline County.

Del. Samuel Rosenberg, D-Baltimore City, who sponsored the bill on drones, said while intrusive monitoring by law enforcement is not a widespread problem, he thinks protective legislation should be in place to ensure citizens' privacy rights amidst emerging technology.

"We shouldn't wait in this instance until the horse is inside the barn door," Rosenberg said.